Audio using home computer

I have a dell desk top computer. I use iTunes to organize my music. Currently I listen to the music on the Harman Kardon speakers that came with the computer. I'm ready to invest in some high end equipment. Is there equipment out there that interfaces with a computer so that you can store CDs on a harddrive and download music from the internet (iTunes)? I want to use this in my office at home. Any suggestions or places to look?

I really don't mean to whizz on your barbeque, but this is incompatible. I'm not being snobbish, just know and understand what downloaded music sounds like in comparison to well recorded source. If you go this route, certain upgrades need be made to the computer sound card for acceptable results. Probably the Swan amplified speakers would give you better than expected results. Good luck.
Here is an Audiogon link to a computer-based system that works well :
You should look at the Wavelength audio line of USB DAC's. Forget about using a soundcard, and feed iTunes out via USB to a compatible DAC.
Try to post your question under PC Audio forum to get more responses.
If your computer has a digital output, you can get an inexpensive Home Theater receiver and go into it's digital input and get the speakers you want. If no digital outs are present, you can take the mini-plug out that now goes to the HK speakers and use a converter to RCA then send the signal to any preamp and amp combination or receiver.
Suggest you check out the squeezebox here:

Good luck!
Burwen Bobcat DAC. Specifically for replay. Levinson/Red Rose quality.
Let me see if I can put it all together in one post for you:

If you are looking to improve the sound, first off you should be ripping files in either a lossless or an exact-duplicate file convention. EAC, WAV, and or Apple Lossless are a few. Ripping files, or downloading them as compressed versions such as MP3 will not result in very good reproduction in my experience. No matter how good the components you stick in between those files and your speakers they will not be able to accurately replace the information that is lost in compression.

The critical stage of what you are considering is turning the digital bits into an Analogue signal. This is what a DAC does. You can do this a few different ways, the two most effective of which are going with some USB interface like a Waveterminal U24 (my choice, though no longer available) which takes the USB output from the computer, clocks it, and converts it to an S/PDIF signal which can then be fed to a conventional DAC of your choice. This can be a superb solution, depending upon the interface device you choose, as can be going with a more direct solution of a USB DAC like the Apogee or Wavelength or Burwen (there are others and their numbers are increasing). In those case you do not need the interface as you are going straight from the computer into the DAC. From the DAC you can go either directly to a powered (amplified) pair of speakers - there are many professional monitor speakers that have amps that do a good job, or there are inexpensive alternatives like the Swan M200's which sound pretty darn good in spite of their $200 price tag. I have no doubt they will best the HK speakers that came with your Dell. You can also feed the DAC into your home stereo system or HT and get the full-on fireworks of going that route. Pick your poison.

The Apple Airport Express, and similar wireless devices, allow you to broadcast a signal from your computer to some other area in your home and either act as a standalone DAC, of which their actual performance leaves a whole lot to be desired, or, in the case of the AE, can also stream digital via a mini-Toslink cable into a DAC of choice and on to either a system or powered speakers. I prefer the S/PDIF connection so I don't use my AE much, though it can be handy if you prefer to have the computer in a different room than your system.

One other piece of advice: If you decide to build up a music library in lossless or uncompressed files, purchase an external hard disk just to store your music. That way it is portable and will not clog your hard drive on your computer. A 250 gig hard drive costs about $200 and will store about 350-400 CD's in Apple Lossless.

Marco- Very good post- Thanks!